Conventionally, various apparatuses of a suspension or a shock absorber of a vehicle includes a strut rod, and this strut rod has: one end coupled to a knuckle arm of one of wheels of a front axle of the vehicle; and the other end coupled to a mechanical assembly of the shock absorber constituted of a rod and a piston and also fixed to a body of the vehicle.
When the strut rod is made of composite material, the strut rod can be fabricated by a single operation and allows a relatively large mass gain compared with a metal strut rod. An expression “composite material” conventionally means a tight assembly of at least two components having properties complementary to each other and is composed of at least a base material and a reinforcing material.
A shock absorber apparatus for a front axle of a vehicle has been known from WO 2014/128131. This apparatus includes a strut rod, and this strut rod has: one hand including a metal inner part provided with a first upper end and lower end; and the other hand including an outer part overmolded on the inner part excluding at least the first upper end. This overmolded outer part is made of a composite material and includes: a second upper end on which the first upper end is folded; a middle part having a cup (coupelle) that defines a support surface for a suspension spring; and a second lower end surrounding the first lower end and including two substantially-parallel brackets, the two brackets being configured to be connected to the knuckle arm of the front axle. Furthermore, the metal inner part includes a first protrusion positioned below the first upper end, and a second protrusion positioned above the first lower end.